pace car vs motorcar

pace car and motorcar both are nouns.

Word	Noun	Adjective	Verb	Adverb
pace car	Yes	No	No	No
motorcar	Yes	No	No	No

As nouns, motorcar is a hypernym of pace car; that is, motorcar is a word with a broader meaning than pace car:

pace car: a high-performance car that leads a parade of competing cars through the pace lap and then pulls off the course
motorcar: a motor vehicle with four wheels; usually propelled by an internal combustion engine

Other hypernyms of pace car include auto, automobile, car, machine.

pace car (noun)	motorcar (noun)
a high-performance car that leads a parade of competing cars through the pace lap and then pulls off the course	a motor vehicle with four wheels; usually propelled by an internal combustion engine